You should use your FT-891 for SOTA (Plus, POTA saves the activation)

Summits on the Air does not need to be synonymous with QRP! If the hike to the summit is short enough and you don't have to bring overnight gear, then use that weight savings to bring more radio! The FT-891 is the perfect QRO SOTA rig as it's only a few pounds heavier than most QRP radios, has a ton of features, and can run at full 100 watts of output power on a 12 AH lfp battery. Here's an overview of my experience with it on Wind Mountain. Also, Parks on the Air saved this activation as I wasn't getting responses from Summits on the Air chasers.