On weekdays, I'm home from work at about 3 pm UTC, so that might be a bit unsure (I don't always get off work on time). 3 am to 6 am UTC, I'm usually asleep.
So best bet might be weekend times. Saturday, I'll be out of the house from about 8 am UTC to afternoon. I could have a server up before that, or after stephan's Starfinder game, which will possibly be finished at about 11 pm UTC (maybe later, there's a bit of uncertainty as it's a high tier game).
Also, there's still the chance that stephan is able to offer other times to have his server up.