USCIS knows that you have H1B and TPS both, as your alien number in both I-797 is same, but that does not mean that you are on dual status. Right now, if you have not used your EAD through TPS, your status is H1B . You can travel to Nepal and apply for H1B stamping which might not be a problem (unless your company has some issue or your background check have some issue), it might take a longer time to verify from DHS but you will get it. Approx time is 3-4 weeks at the earliest.

At the worst case scenario, if they deny stamping your H1B stamping, will you be able to use TPS AP. Sure enough you can , but at the POE they might ask you why your H1B is denied and allowing you re-enter US is entirely at the discretion of the authority. Remember having AP is not a re-entry permission, it just allow you travel outside US.

Now, once you enter US through AP (even if you did not stamp H1B, lets say!), your H1B status is no more active and you are in TPS. So, I would recommend to consult a good lawyer before making any decisions.

Now under the current situation going around, do you think its a safe to travel outside ? My suggestion is NO.