Well you no know it’s not too late to take that cedar off and put on composite!! 😮 😮 , I used Wollmanss stain, it seemed to go on pretty good, and looked good, lasted around tree years, this was on green treated Good luck sounds like quite a job.
My sister and BIL used composite and went thru he’ll getting it right. Manufacturer finally replaced half the decking.
As stated above, if you want to stain/finish it every few years then do that. Don’t want to put up with that much maintenance then power wash it when needed. Just don’t blast the life out of it. Wood is wood, some last longer than others, but eventually it will all need replaced. Personally, I think stains and the such are a waste of time and money.