I've decided to make dry firing a part of my daily routine. With my wfh status I can keep my g19 next to me all day so I may as well.

How many fires a day should I do in average? Any specific drills?

My normal routine is:
50-60 reps standing from a holster (sets of 10)
50-60 standing draws with 2-4 target transitions
30/ea strong and weak hand (weak hand portion is strong hand draw transition to weak hand)
Then i'll go into more dynamic things...tough to describe those here.

For as long as you can remain focused and get something out of it.

Buy ben stoegers book "dryfire reloaded." You can do a lot more in dryfire than most people think you can. You can skip over the gaming stuff if that's not really your thing.

Not about how many, rather how many good ones you can do consecutively. I’ll string out 5 consecutive perfect reps of what I’m working on and then rest for 2 mins. Total session is roughly 15 mins. Sometimes I’ll do 4 sets and others will be 1. All about getting the 5 perfect reps.

^this

For possible reference:

Several people have already mentioned Ben Stoeger's Dry-Fire Reloaded. That's the place to start for sure.

A key thing in dry fire is to grip the gun HARD, just like you would in live fire. If you're doing this, it's unlikely that you'll last more than fifteen minutes before your forearms are smoked. I personally dry fire twice on most days, fifteen minutes at lunch and fifteen minutes after work.

As for what to practice—anything you'd do on the range. Draws, reloads, transitions, shooting your way into and out of positions, etc.

The value of dry fire is proportional to the honesty with which you approach it—getting adequate sight confirmation for the shot, gripping hard, isolating your trigger pull, etc. It's good to mix live and dry fire on the range to verify this.

Newbe question: I'm looking at a dry firing systems for both my P365 & P320 M18, I like the idea of being able to track how I shoot.  I like the mantis X3 and have a few questions.
Do in to use snap caps so I don't damage anything?
Do I need a snap cap that will not eject every time?
Is the mantis X3 my best choice in dry firing? If not what is?

With the ammo situation I want to improve my dry firing with a laser bore sight.

Everything I find seems to want to only fire on a trigger press.

Is there one out there that stays on so I can just focus on not letting it move as I work the trigger?

https://www.amazon.com/gp/product/B0794YFRYP