While on H1B, you can apply for TPS with EAD but do not use the EAD and continue working on H1B. If you change the employer with H1B, you have no problem if you transfer your H1B to new employer but never use EAD. Once you use EAD, then you violate the H1B work authorization.

Context: If your job is terminated, your H1B also terminate and you are out-of-status immediately.So in that situation, your TPS will protect your status and work under EAD.

I do not know if there is any grace period for H1B if your job is terminated, if there is any, you can look for another job and transfer the H1B.

So TPS with EAD gives you benefit if you face such situation.