Whatever you feel like doing, do less than that in both duration and intensity, and probably nothing above z2 until you’re definitely at the tail end of it (either by symptoms or by waiting a few extra days).
I planned to keep doing easy rides, but pretty quickly I didn’t want to get on the bike at all so just focused on rest. If in doubt that’s always the better choice than taking a risk on your long term recovery.
There’s a good guide linked in the Well… I got COVID. Starting over thread.
I trusted those guidelines. Was off completely for two weeks with symptoms and positive tests, then had a recovery week scheduled so just kind of rode what I felt like and didn’t worry about either taking it easy or building back up. This is now coming to the end of my first loading week of the next block (week 4 since getting sick) and I’m very very nearly back to where I left off. Also lost about 1kg while I was ill so it’s hardly been a setback at all.
Better to be too cautious than too ambitious. Too many awful long covid stories out there!