I can do my oil own changes as long as I keep recepts for the oil I bought
That's a problem right there.
I buy my filters in bulk... a box of 10 is about $40, so in 2020 at 100k I'm going to be using the last of a box of filters I bought in 2016.
Likewise for oil.
Once or twice a year, Costco puts Mobil-1 on sale... it's like $27 for a box of 6 quarts, limit 3 boxes.
I'll hit up 2 Costco's and buy 6 boxes... maybe not so much now with the Rav and Corolla being on 10k intervals, but that's still 2-3 oil changes a year for my Corolla... wife runs about 15k per year.
The receipts really don't prove anything other than you bought oil.
It doesn't prove that it actually went into the car when it was supposed to, you could have re-sold it to a friend.
Even in the owner's manual, Toyota says that they will NOT deny warranty service simply because you do not have receipts for service.
Honestly? They can tell when they open the engine if a failure was due to lack of maintenance.
But it does provide an easy out for 3rd party service contract providers.
HINT: Scan and print copies of your receipts. I've pulled receipts stored in my desk after several years and they are illegible... black thermal ink fades and the paper yellows.
Receipts stored in the glove box or garage? Blank paper in 6 months.
$70 seems like a lot but considering its 10k or 1 year it's not that bad
Not as bad as $70 every 3k, but consider you can buy 5qts of 0w20 M1 at Walmart for just under $30, and the OEM filter is $5....
Also, I don't know about your dealerships, but those around me, it's a 4-hour ordeal even with an appointment.
If it dosn't I'm going to buy a megaphone walk in to dealership I bought it from and announce my findings on there busiest day to everyone buying a car lok(it was really busy when we're there almost like a restaurant at lunch time)
Meh... all that will do is get you booted, possibly arrested for trespassing and a restraining order.
If you own guns, you do NOT want a restraining order. My boss went through that already.