blind vs blind battle vs highstakes reg playing lowstakes

Hey guys in this tournament I had 8 chips and finished 3rd.

Unfortunately the highstakes reg who played too came into the final table as slight chipleader above me and was able to choose the seat exactly to my left with position on me.

we ended up playing a few blind vs blind spots.

Im quite unknowing when it comes to blind vs blind battles and would love to hear your comments on my plays

preflop? river call?

preflop? barrel postflop?

preflop? bluff river?