How much can you lift/do you lift?
Personally, power cage over squat rack.. More uses and a bit safer.
Eg
https://www.amazon.co.uk/Mirafit-Power-Rack-Weight-Lifting/dp/B00QACJQWK
Max weight 250kg, £140.
Squat most of us wont ever get near to 250kg, deadlift you do from the floor (generally) so no limit (unless on suspended floor....) and Bench again you probably wont get near to 250kg.
Shrugs are one exercise where you might regularly be pulling 250+kg (or that might just be me
), but if your a way off this then something like that would be ideal.
And you dont have to design/build it yourself, with which comes all the questions of 'is it strong enough AND stable enough?'
LAST thing you want is something going wrong with your safety equipment (which is what this is) when your having a wobble at your limit of lifting. And that doubt about the kit is also a problem, stops you progressing.
If you are prepared to go second hand, have a socket set AND have a way to transport (mate with a van, suitably bribed) you can find some absolute bargains about!