Wasn't there a sweet spot somewhere in the Venus atmosphere that's more Earth sauna like, than the hellish surface of Venus?
https://selenianboondocks.com/2013/11/venus-isru-what-do-we-...
Which as far as I can tell isn't terrible if you don't breath it in and if you do the official allowed exposure time is 10 minutes for 5 ppm. I would recommend you wear goggles in addition to breathing equipment, though.
Presumably that's 5ppm under terrestrial conditions, Venus at 40km has substantially higher pressure, more than is explained by the higher temperature alone, so any given ppm is a greater number of molecules per cm³, right?
The Wikipedia page on Venus's atmosphere suggests that at that altitude Venus's atmosphere is a sulphuric acid haze at 110°C and about 2atm of pressure, which, even if there was something to walk on, doesn't sound like you'd be able to walk around with just an oxygen supply for very long.