I don't think you need more than N95 for protection from airborne viruses. You can go up to P100, but it will make breathing harder. Your biggest win would come from getting a well-fitting elastomeric mask/respirator with N95 filters, and ideally, no unfiltered output port (for other people's benefit).

The single best thing you can do to ensure you're protecting yourself is to do a home fit test. Surgical masks, KN95s, N95s have generally the same kind of filtration layer; the essential difference is the fit. Is it sealing on your face with <10% leakage, even when worn for long periods and while you speak and make facial expressions? You can't really know this for sure unless you do a fit test.

It is pretty cheap and easy to do a DIY fit test.

Here's a video that explains how to do it with a trash bag, some Splenda, and a $7 nebulizer.

Here is a written guide.

A p100 with an exhalation valve. I use a gvs eclipse because it looks the most "normal" and is light so it's comfortable for long stretches. Got it at Lee Valley, have seen them on Amazon.

Edit: you won't be protecting others with this mask, I'm not worried about that because I live like a hermit. If you are then follow @TrashGoblin@hexbear.net's advice

The only thing about n95 is p100s. Idk if they even make p100 face masks. At that point you're looking at a half face or full face respirator.

You can get N99 or N100 masks. I haven't seen any that don't have a valve for breathing out so they don't protect others, just yourself.

For masks, the convention is that the number is its ability to filter out small particles and the letter is for whether it also protects (P) against oil-based particles or not (N), with R offering partial oil protection. There's nothing wrong with using a P99 or P100 but it's probably not doing anything more than an N99 or N100 for airborne diseases.

The silicone respirators that you can hook N/P100s to can be pretty nice. They have better airflow, in my experience, but are also much heavier. You'll get a wet face using one for hours.

As others mentioned, fit is important. If you have a gap in your seal you've kind of defeated the difference between N95 and N100 already. If you have facial hair, shave. Then fit your mask to your face by adjusting the nose thing or the straps if they are adjustable. Do some rapid breaths in and out and see if there's pressure/vacuum.

Also N95 is probably enough for the vast majority of scenarios. Given that money is limited, it might be better to buy many N95s rather than fewer N99s or N100s so that you can rotate them. I keep around the higher-Ns for occasions that seem particularly risky like poorly ventilated areas packed with people.