Flush on turn - sizing and line check

As played: You can safely bet turn. You don't represent many flushes since your flop line is by no means "standard" (it is actually a bad choice). Also, by not betting, any OTR will dry up the action.

should we always donk flop then multiway with FD ?

It is an option. It builds the pot and somewhat more than a check-call masquerades our holding if we hit. The check-raise, on the other hand, is a much more expensive way of bluffing that most likely will end up heads up out of position on a missed turn in a big pot. This is not comfortable. By donking (or check-calling), the pot is more likely to be 3-ways and reasonably big (this is what we want). But don't donk turn against two players those times you miss.

There is no need for flop raise, hero is getting good odds for calling.
As played, bet small turn and river, don't let villain to xb turn.
OOP I would lead and bet flop/turn with NFD.

I would bet flop myself here.

vs a fish is good to call Ats here in SB, but if both are regs, fold o 3b sqezee .
in a mwp vs a fish is too better to call draws comparated to x/r or lead becouse u get so much odds and implied odds vs fishes here .
if u have over pairs or sets o 2 pairs here is better to lead !!

the problem is that I have seen so many advice for donking on this type of flop : donk :

sets
overpairs
2 pairs
flushdraws ...

don't we have a c/r range here ?
or c/c range ?

while others say : donking is for donkeys ...

In multiway pots when you want to continue with your hand it is better to bet yourself and take the initiative than x/c and risk that everyone checks behind.

I would bet turn and bet river. As played we missed value.

No need to hold back at the micros. Just bet for value. Even if villain would fold somehow, it is better to let him fold many times but have 1 time have him call a huge value bet from you than he will call small bets because in the end, it is -EV when you lose value.