Detailing steps - same-o same-o or do I up my game?

Hello, I'm pretty much a novice detailer although I've been washing and 'detailing' my 2019 dark gray Silverado for awhile now. Here's what I've been doing for the last few years.
1. Every spring, I live in Michigan, I spend 500 bucks at a detailing shop for an inside / outside buff and clean.
2. Then every Friday through the fall I wash with Optimum No Rinse and then use Maguire's Ultimate Quik Detailer spray over the whole truck. I use many quality fiber towels. I'll go thru a brushless car wash if its real dirty before I do my cleaning. I don't drive it much, 23,000 miles on it right now, so it doesn't get very dirty usually. I'll do the tires with a Maguires tire cleaner also. I spend some time on the inside and I get the windows streak free but the outside is where I spend most of the time.

Thats it. It looks pretty good if you ask me. But I'm wondering if its time to change my routine. I'm retired so I have the time to do more if need be.

So my questions are numerous but I'll try to keep them understandable and at a minimum.

1. What would a slightly more advanced routine be?
2. Buy a buffer polisher? Which one? Something less than $300. That eliminates the detailing shop, correct? I dont have many but do these buffer polishers get rid of swirl marks?
3. If I buy a polisher how often do I do that? Every week? Can you buff and polish to much?
4. Do I still use a detail spray? How often? And can you do that to much? When are you just adding a layer of spray detail to last weeks?
5. There are a ton of products to use. Any recommendations for each step?

I guess thats it. So if anyone has a 'better' routine based on what you just read, and your willing to lay it out in steps, I'd appreciate reading your answers.

Thanks,
123rdm