@EHO_AZ is correct on all points.
I suspect that failure to decarb is your biggest issue.
Yeah, that trick is for concentrate, not the flower (Decarb under pressure to retain terps?).
You will find very few professionals who decarb before extraction, because it’s much easier to control and trivial to see the end point if you extract first.
Most commercially available tinctures are also concentrates bought back up in an oil carrier (for this very reason).
You could certainly extract with ethanol, recover all your solvent, decarb, then bring back up in oil.
Ethanol tinctures don’t actually age well in jars (might go dig that up later…)
80mg/ml it you got it all and decarbed it. How much are you taking? Got any data on how much YOU need?
If you’re only getting 80% of what’s in there (and the coa is accurate) how many mg of thc are in your 50ml tincture?