You may be surprised how well a panel saw will work. It will have a larger kerf, but if it is tuned well so that it cuts straight and without jaggies, it will be fine. Ideally, you’d use a saw sharpened for cross cutting, but since you will put the back of the work against the miter guide, you might even survive with a rip if the tpi isn’t crazy.
Why not make a miter guide and try some cuts, see how it goes? I’ve done this before with tall trim moulding and it was fine. The realities of imperfect walls is likely to make more of a difference than the saw. Remember that, if you cut your miter guide for 45 degrees and the wall is a bit off of 90, you can put a shim behind the work in the guide to adjust the angle a little bit. A shim is often a plane shaving or two. If you put the shaving near the saw blade you will have the opposite angle adjustment than if you put the shaving away from the blade at the end of the guide.
Keep an eye on your guide. Depending upon how much work you need to do, your sawing style, and maybe the saw, you may need to make more than one guide.