New to me prius maintenance

Just want to say thank you everyone for the helpful information posted. With everything being said, since I plan to keep this for a while I have decided that I am going to buy a replacement manifold and EGR system pieces and have my mechanic replace them with new parts and clean the old ones for the next time around maybe 250k or so and go ahead and have the head gasket replaced as preventative maintenance as well while I am at it to hopefully be able to keep this car for a while.
I will also go ahead and have the transmission fluid replaced as well as spark plugs and coils. I have already cleaned out the MAF sensor. Since the battery is not good but not quite bad yet, I am keeping an eye on a lithium replacement and unfortunately just missed the blowout sale they had.