What is pay-to-win?

This video popped up on my feed and I thought I'd take a look as from my time in World of Tanks (WoT) one thing became clear, there really isn't a consensus of what is, and isn't, pay-to-win. The video is a bit long and dry but one of the things that resonated with me is there's pay-to-win and then there's pay-pay-pay-to-win as what money can give you is a sliding scale.
https://www.youtube.com/watch?v=wgNT72xzv1Y
To me it's really can paying give you advantage over an equally skilled player and/or does it effectively stop me enjoying a relatively full game experience. That doesn't mean I think it's instinctually wrong as it depends on the practical reality of that advantage/experince and that's the model you knowingly enter. So I'll use WoT as my example as, well it's the only game I've played that i consider to have pay-to-win elements.
In the early days the elements were pretty sparse so you had premium tanks which earn more crew exp./credits but that came with the downside that were slightly worse than a fully upgraded normal tank of their tier. Then you had premium consumables (in-game gold only) which were just better than regular ones and the ammo was one that made a particular difference. This didn't bother me as the cost for running it soon added up and the impression I got was because of that is was very rare to encounter a player 'spamming' it. Th big one was premium time that earned you more exp./credits. I didn't have a problem with that as at its core it was about paying for time not in-game advantage.
Over the years that changed due to premium consumables being available for in-game credits, and what was the best way to generate them - paid premium time/tanks, but the thing that really changed the game was the introduction of premium tanks that were just better than their free equivalents. That was then compounded by bringing out a tank that was clearly over powered and putting it in paid lootboxes.
Overall it was one of the reasons I got less and less interested in the game and eventual stopped playing it. It was the way that the desire to slowly ramp up the 'encouragement' to spend more and more money* started negatively impact on my game experience. Indeed it got depressing to play certain tiers where the battles were stuffed with the latest and greatest premium tanks.
I won't cover all the more minor changes they made in-case anyone who's got this far falls asleep!
So thoughts from anyone else, do you hate pay-to-win, think it's a good thing or is it more a case of it depends?
*Mind you it worked overall and the amount of money some players admitted spending was eye watering. One of the worst, or most ironic examples, was a player whose garage was stuffed full of premium tanks and had probably spent over £1,000 in about six months. The ironic part is that their win-rate was basically the same as if they entered a battle and then didn't touch the keyboard or mouse.