I don't usually interact but this made me think. What if.. instead, we combine the two solutions?

1. Any rentals for the current season cannot be cancelled meaning if I rent 4 days and the season has 7 more days left, then the renter cannot cancel that rental early. This also apply to the one who rented.
2. Any rentals past the current season may be cancelled at the end of the season. This is for adjusting the price favorable to the one renting. We don't want them to rent low now and someone rents their cards for 4 years and they cannot adjust the price for it. So, add an optional part that the one renting can cancel the rent at the end of the season.

As for the tournament problem, then just combine the rental cooldown and delegation cooldown. For example, if you delegated the card and cancelled, and the cooldown is for 48 hours, there would be a warning that the card cannot be used for 48 more hours. Or an easier way is that you cannot rent/sell cards with delegation cooldown.

With these things,the community can still rent for 2 days when they have the time to play or rent for the whole season if they play everyday. The daily and season rental is like combined into one which I think does a compromise for all issues.

I rent 2500 DEC worth of cards every 2 days. So putting it to seasonal, It FORCES me to have 18750 DEC (1259/week x 15 days) to rent for the season. If I only have 5k budget per week, then I will be FORCED to wait until the last 5 days until I can play because I only have 5 days worth for my weekly budget.