yeah those plexiglass cutting blades can't cut angles. They can only cut straight lines. Hence why they aren't ideal for projects.
If you want to cut through plexiglass like butter, you're going to need a soldering knife to cut it.
Do you have access to one? If not I think I can help you out maybe.
When in doubt, just take the next small step.
With that next step take a deep breath. It calms the mind.
When the mind is calm you realize the best is still yet to come.