I went back to work full time at the start of the year and then negotiated 0.8 in April. DS was initially in daycare 3 days a week and now 2 and he goes to his grandparents the other 2. I have no guilt, DS loves day care and loves his grandparents so it's win-win for me!
I have a fortnightly cleaner and a Gardner to maintain the yard every month or 2 depending on season. Without that help id go insane and the cost isn't very high for the sanity it gives me. It also means I don't clean on weekends or days off beyond washing and general tidying and gives us lots of time to spend together. I just do tidy ups at the end of each day and a few quick wipe downs of surfaces/vacuuming in between and the cleaner does the rest.
with this arrangement I find working 0.8 really manageable and I fortunately have a manager very conscious of work-life balance which also helps a lot.
Agree with pp above perhaps try 0.7 and see how you go if you don't want to jump straight into 0.8.