In the “Prosumer” and “SME” space UBNT are pretty much the default choice for a WiFi access point. They’re not stupidly expensive, reliable and easy to scale.
The UAP-AC-LR is still an excellent access point. What are you trying to achieve from your upgrade?
How many 6GHz WiFi6E or WiFi7 clients do you have? Current UBNT access points have excellent resale value used so personally I wouldn’t be put off buying anything from the AC or U6 ranges new or used because WiFi6E and WiFi7 are still very much niche products, mainly for people doing VR. You still have to spec WiFi6E as an option on most laptops as an example. Most folks want great coverage for their handhelds and IoT devices. Most of those are still 1x1bgn, 2x2 AC or sometimes 2x2AX so your UAP-AC-LR should still give you 200-350Mbps on 5GHz depending on distance from the access point and obstructions between you and the access point. Adding an additional access point like a U6-lite or U6-mesh will probably get you better coverage but for most uses no better speeds. I still see far too many ceiling access points lying on tables or mounted vertically on walls so if that’s you, swap that orientation for ceiling mounted or an Omnidirectional access point like U6-mesh. WiFi6 OFDMA gives benefits if you have lots of 1x1 IoT devices because AC has to run at the speed of the slowest devices connected so your 2.4GHz could be crippled by your doorbell for example.
The U7-Pro is a great access point and if you have a WiFi7 client you will see transfer speeds in excess of 2Gbps in the same room as the access point. If you live in a barn conversion you’ll be delighted. But other than the “future proof” idea you’d probably be better waiting for WiFi7 to resolve itself before you spend money on an access point that may never actually work in the UK. The licences for those wavelengths are still very likely to go for cellular 5G use because the government earns money from the auctions of those licences so at this point in the UK a WiFi7 access point could be a total dead duck. A Wifi6E access point is actually usable at the moment (my iPad Pro is wifi6E) but even then how many WiFi6E devices do you have?