Creative line, stakkedoff!
I analyzed your hand in GTO Wizard:
I like your XR on the flop. You've got the spade, nut-gutshot, overcards. QsJx is a great semibluff candidate.
On the turn, the solver agrees with DooDooPoker - use 1/3 or X. This is very common on flush-completing turn cards.
We can see that the small size is preferred on most spade turns, whereas a larger size ~75% is preferred on most non spade turns. The frequency of your bet has a lot to do with how many of your OESD/Gutshots the turn completes.
On the river, the solver prefers a 35% block-bet-bluff. The 3 isn't a great river card for you, unfortunately.
The block-bet is composed of flushes and air:
In general, the paired river mitigates the strength of your flushes, which comprises the majority of your value range. As you can see the equity distribution isn't fantastic for your range:
Nice line!
GTO Wizard