There isn’t a significant difference really... in the 13” MacBook Pro, the 8th gen chips are 15 watt TDP and the 10th gen chips are 28 watt TDP, but the 10th gen model has more robust cooling with larger heat syncs and a second cooling fan.
I had an 8th gen and send it back and got the 10th gen. Both run pretty cool. Never felt much of anything. But I use my MBPs on a desk or table, never in my lap. I have an iPad Pro for that use case.