Schoen Gruesse Aus Engeland. 
Opening tilt windows at the top by 2.5-5cm is fine for your situation, I leave my top 1/4 window open all the time.
If you can arrange air-flow away from you to window, then that is better.
Sanding dust settles reasonably quickly. Just keep your workspace clean. You can always wet-sand with auto parts store wet paper. (ALWAYS wet-sand RESIN model parts though, resin dust is harmfull and not pleasant)
I use 3M 72xx (01/02/03 = S/M/L) series mask, with replaceable VOC and N95 dust filters, keep filters in zip-lock bags when not in use.
I have a full beard and wear glasses, no problems, wear it all day for DIY work (with dust filters). I replace filters when clogged.
I only, (but always) use it when spraying acrylics and gloss/mat topcoats, (Covid19 damage). I no longer use enamels.
I also have a home-built spray booth, 4x 240CFM fans is probably overkill and LOUD, so I only use when spraying. Exhaust hose goes out of window.


All acrylics are a form of resin, with differing carrier mediums, water, to cellulose/lacquer, and not recommended for breathing. Brush painting schuldn't be an issue.
My concern is with bedroom & bedding dust (been there, done modeeling in bedroom...) consider a transparent storage box to keep dust off model when drying.
Also Cats.... Boxes, if it fits, it sits! 
Remove from modelling environment. 
The housecat was banished as it considered my workbench it's play area and my models as chewtoys....