I hope I understand your question correctly and hope this helps.
So, it sounds to me like you won't be able to renew your OPT EAD (because non-STEM). If this is the case, then it further sounds to me like you want to work and don't really want to go back to school just yet (or you may be thinking why do it if you don't have to, which is completely understandable). So, if both of these conditions apply to you then I would suggest you to apply for the TPS EAD. I mean, besides the cost, it will, in no ways, harm you. You will still be in F1 status until your OPT expires, TPS EAD mai kaam garna thalyo vane pani. I am assuming here that school ma valid employer ko info and such diyeko chhou, tyo info haru change nagarnu school sanga iff TPS ma kaam garna thalyou vane. As long as school ma employer through kaam garira dekha ko chha F1 status jadaina. Furthermore, 1st year OPT ho vane ta jhan school/kasaile khasai tyasto waasta gardaina. STEM-Extension (after the 1st year OPT) ma chai ali garo hunchha baru.
If the above situation does not apply to you, and instead, you can extend your OPT EAD (STEM degree ho vane) OR you are just wondering how long it takes for the TPS EAD to arrive so that you can plan things accordingly, like the person above said, it usually takes 2 to 3 months. Sometimes, the TPS EAD arrives really quick as well i.e. within a month.