I believe it would be fair,only for NT and U-21 players, if they got TLed, their respective country teams to have a kind of first option, on bidding.
I mean, when a NT players gets listed for the first day or two, only his country's teams can bid on him. If he gets even one domestic bid, then until the transfer deadline only other domestic teams can outbid.
If he doesn't get an initial bid from his country in the afore mentioned (initial)deadline, then the rest of the world can come in and bid for him.
My reasoning behind this, is that the already existing problem, will intensify going into season 24.
When the 2 week drop in GS comes into play, a purchase in order to harm an opponent NT, even if its for a week and then the player gets sold again, can ruin the player's entire NT season.
Additional provisions, regarding GS for NT players will have to be made, as well.
For instance, im told that very recently there was such a buy.
NT1 has a 230k player. His team put him up for transfer. A division III from another country went into a bidding war and got him.
The DIII team is from a country that plays soon against NT1.
The DIII team already has a +200k domestic NT2 player and then 5k scrubs. We all understand whats going on here...anyway.
The player of interest has got in the first two games with his new team, 92mins of play and the week isn't over yet...
Put this real scenario into next seasons GS changes. The player gets bought by a countryman of an opponent NT. He gets a big drop in his GS. Then lets say he stays there only for one week, gets another drop by being overused and then he gets transfered and he gets another 2 week drop! In one single week, his entire NT season(at least) is screwed.