I commuted daily into central London for 25 years from numerous places, Woking, Brookwood, Basingstoke, zone 3 , Barnet, Redhill, Ashford and Wye. Here's the advice I give anyone who ever asks me from my experiences. Consider the following things:
Cost
For both your current situation and desired future state compare housing and commuting costs together. Sounds obvious but people forget bits. Particularly first timers out to the suburbs forget things like the parking charges at the station that you don't incur if you're used to London and public transport only. Also sometimes forgotten is the increased maintenance costs at home. Sure for the same rent/mortgage you'll get a bigger place. But it costs more to heat, needs more maintenance etc. I recall a big shock for me was the fact that my lovely new big garden needed either money to pay someone or a day of my time every single weekend Spring - Autumn keeping on top of it! I love the dozens of trees surrounding the house but I hadn't factored in the £3K every five years to get them lopped nor appreciated the cost to replace the fence around the perimeter of a third of an acre (that's £5K+). Suddenly the ground rent and service charge of a leasehold flat that I detested paying so much didn't look too unreasonable.
Door-To-Door Time
Forget the headline train time alone. At the "home" end, how close is the car park to the platform? How long is the drive there from your house? How much buffer do you have to give yourself to catch a particular train? How many interchanges on the tube when in London? How long is the walk from your final tube stop to your place of work? How many trains an hour in case you miss one etc.
How important is time in London to you?
Do you enjoy a drink after work or to go to a show? If so then consider, do you need to be within painful but not impossible cab distance back home after a bender? If you like a drink is there a cab rank at your home station or how else will you get home? How will you pick up the car at the car park the next day? What time is your last train home? Will you go into London at the weekends? If so how does the train service deteriorate at weekends? How much extra will it be for the family to join you?
What will you do at home when not working?
Many, many commuter towns are just depressing, particularly if you're used to the buzz of London. Guildford, Brighton and Cantebury are about the only ones I know of that have something about them. Wherever you pick you need to be up for enjoying things that are not urban-centric. The seaside, the countryside, dogs, touring national trust properties or whatever. Of course there's more than that but if you don't get some joy from a non-urban lifestyle then don't do it.
Quality of Commute
The most often over looked thing I think. I moved from a 13 minute train journey as part of my commute to 40 minutes. (door-to-door changed from one hour to one hour and a half). But I am much, much happier doing the longer journey. Why? It's on HS1. Everything is air conditioned, the journey is smooth, all the seats are international class with leg and elbow room, I always get a seat with power and a table and it rarely breaks down because old rolling stock doesn't use the line. I enjoy the 40 minutes to catch up on a TV show as opposed to being jammed into a tin can elbow-to-elbow hoping I can contort myself enough to read the sports pages in the Evening Standard or Metro. I arrive at my destination relaxed. The frequency and quantity of interchanges in London and tube line you use also play a part in this. For example I can now get to the West End door-to-door in an hour and I have only the High Speed and an air conditioned spacious (comparatively to many lines) tube trip changing at Stratford onto the Elizabeth Line which is an easy walk through a shopping centre.
Also consider being one station out form the main hub at your home location. It's been mentioned a few times here but trains sort of stop and then are fast from a certain point onwards. Being one stop out can often mean the difference between a seat and no seat in the mornings. I found this when I commuted from Brookwood (one stop out from Woking). It was much more pleasant getting a seat at Brookwood than standing room only from Woking and only added 5 minutes to the journey. Closer to town on that line, easier to get a seat at Walton and Hersham than at Surbiton etc.
What will you do if your job changes?
You can plan for current circumstances but what will you do if things change? The terminus you arrive at and area you live in play a big part. For example in the IT industry I think I'd feel much more secure commuting from the M3/4 corridor since I would have both London and the corridor itself as places of employment.
Now interestingly I actually worked and commuted to a location not so dis-similar to yours OP. Baron's Court as opposed to South Ken but on the same lines. And I commuted to it from Woking, Dulwich and Wye in Kent at various times. Kent made me the happiest. HS1 is such a joy comparatively to travel on other train lines and a simple change at St Pancras onto the Piccadilly line made for an easy commute that would let me relax with one TV episode (train) and one podcast (tube). I live in a country house in a village rather than flat (London) or semi (Woking 'burbs) and I enjoy being less than 30 minutes to the coast and being able to walk out into fields and orchards. Not without its downsides - commuting cost was huge (£900 a month - but I don't do it anymore) , could never be spontaneous in London (cab £300 home, trains stop quite early and get infrequent quickly after rush hour) and uber/delveroo are non existent locally. Also not pertaining to me but I think if I had a family then you'd have less time with them in the weekdays which I would think is a down side.