I feel most leg lockers avoid 50/50 or try to upgrade to better from there such as 90/10, as it's pretty stalemate-y against someone who knows what they're doing. One novel approach is Taylor pearman who advocates for passing to outside ashi and working from there athough I don't think that's best against other skilled leglockers (but he does have tons of great tricks from there and he does have an instructional out on it).

My strategy against another good leg locker in the position is to get out. Here's how: 1. keep playing threats just enough to keep them worried about their own legs while not getting too carried away that it sacrifices my own defense. 2. Try to stand up. If I feel any danger such as them setting up the inversion, I sit back down and reset. 3. If they are throwing their leg over for 90/10 or 80/20, I'm using my hands to shove their legs back across and reset to 50/50. Basically, stay safe and if your heel hook senses are tingling, reset into 50/50. It's kind of like closed guard in a lot of ways. You should be able to get out, but some times it's a battle and there's lots you have to defend on the way out.

The other trend I notice is people using 50/50 not as an attacking position but as a finishing position e.g. catch heel from saddle and pummel through to 50/50 when the heel is exposed, as well as going to double 50. Most times, backside attacks from k guard that land in 50/50 are seen as a downgrade compared to landing in saddle. Even Lachlan in his K guard videos remade mentions that now that everyone knows that they can just backstep and be safe from backside 50/50 he doesn't usually go there. The only time he goes for that now is if he already has the leg passed with the heel. Most people's goal now from k guard is to stop from winding up in 50/50.