@TimmehSounds like congestion in your local area, which can happen at peak times..
If you drop down to 3G is the network any faster.
It may also be worth checking if there are any service issues in your local area by going to
https://status.o2.co.uk
- Xperia 1V - o2 and Spusu
- Pixel 8 Pro - o2 and Vodafone UK