A non-hockey padded compression shirt might be a good starting point. They’re basically compression athletic shirts with a few pads in the shoulders, sternum, and lower back area.

I started wearing one as my undershirt under the jersey in non-serious skates, and now primarily wear them except for a few more competitive games. They’re not a substitute for full on shoulder pads, but a good intermediate step if you’re worried about discomfort. They’ll protect you against hitting the metal dividers on the glass, and mostly prevent a few bruises.

Here’s the one I got, but there’s a million different ones available. https://www.amazon.com/dp/B01MDURPUH?ref=ppx_pop_mob_ap_share