Yeah I mean my old iPad just about manages what I do now but I do want something that will really last so I can stop thinking about this stuff!
Performance-wise, I expect faster single core CPU from Air 5 but more or less similar performance in terms of multi-core CPU and graphics.
Apart from Center Stage, I don't think the Air 5 will be getting any features that will make it better than the 2020 Pro. Perhaps on par, but not better. I do expect better battery life though (5nm iPhone chipset).
Storage and RAM are unknown at this point and could swing either way but I don't see the Air 5 getting more than the 2020 Pro's 6GB/128GB base.
If TouchID, chassis color, faster single threaded performance and power efficiency aren't priorities, I'd personally just go for the 2020 refurb.
With that said, the 2021 iPad Pro with M1 and 8-16GB RAM is a good option with greater headroom for just a little more. At least in the US, I've seen it on sale for $699 which is just $90 more than the 2020 refurb. I don't know if you get sales like that in the UK.