I believe that there should be a middle ground in here.

For example, keep them partially soulbound in a way that they cannot be delegated or staked in land, but that they can be rented (so that new players have a way to access them without paying through theyr nose, specially with the gladiator cards being OP on bronze), the difference is that since they are "soulbound" it could be made that there is a fee to temporarily make them unbound for this rent, and this fee could be a % of the renting paid value, for example a 10-50% of the rent price being sent to DAO/SPL/Burned, which could make a good dec sink or income source.

Also notice that I did not mentioned selling since I am unsure this would work even with a fee since it would kill unbinding and it will give the bots an exit liquidity that could damage the ecosystem more than it would help