On the CurseForge page, I saw in the FAQ:

_Why don't guards have a workstation like other villager professions?

I haven't thought of a suitable block that would let you have a large number of guards without being inconvenient to store._

Instead of a single workstation for them, you could make a few different ones that have the same effect. This way you could spam workstations without being repetitive.

As for what blocks, if you need vanilla blocks then Bell and Campfire would be good choices as they wouldn't stand out and are not currently workstations.

If you would rather add a custom workstation, then a weapons rack would look cool and you could make an armory structure that generates with villages to house a few of those workstations.

Got ahead of myself and didn't read the notice about suggestions.