I've been selling my prints for years, and have always relied on an Epson printer for the best quality.
You're keen to do larger prints, so this would mean you would need a large format printer, which can be pricey.
The Epson Workforce Pro wide format series of printers will print up to 13 x 19", and comes with a scanner too so you can scan your stencils-but only up to 11 x 17 ".
Here's a link for comparisons of different brands of wide format printers: https://www.pcmag.com/picks/the-best...ormat-printers
Bear in mind that inkjet ink is extremely expensive: you can use third party ink but in my experience this eventually ruins your printer, so I only use Epson ink for my Epson printer.
As for paper, again, it is pricey if you want to do wide format printing - Canon seems to be good, but I still go with Epson, for eg: https://www.bhphotovideo.com/c/produ..._archival.html
When I started out selling at markets and fairs, I sold my artwork as greeting cards and smaller 8 x 10" prints, to see which one sold best and I also had them printed by a printing company (like Kinkos) before committing to buy myself an expensive printer, again, to see what was working, and if it was viable to sell my prints commercially.
I hope this helps- good luck!