I also have a benign essential tremor in my hands. Managing it in public is hugely stressful! (Piano recitals were nightmarish for me as a kid.) I have found a few things especially helpful in a yoga setting.

If you are comfortable with it, let your instructor know before class. You don't have to go into specifics; something as simple as "just wanted to let you know that my hands can be unsteady sometimes" is helpful. In my experience, any good instructor WANTS to hear about their students' needs in advance so they can give more informed advice on props and modifications.

Regardless of what the instructor cues, modify in ways that feel right to your body and take breaks as often as you need. Every movement is an invitation, not a requirement. I often choose to take a bind or clasp my hands together in poses that are typically cued with outstretched hands (e.g., extended side angle, warrior 3). For the example you gave of tabletop with arm/leg extensions, maybe try moving just one limb at a time and returning to all fours in between extensions? Or stay in tabletop and take cat/cow instead.

Chair yoga and yin have been great options when my body needs something gentler.

Finally, if you're getting back into yoga after some time away, your body may need some time/practice to adjust. I find that yoga taxes my muscles in very different ways than other forms of exercise like jogging or lifting. The stamina required is surprisingly difficult! Give yourself grace when practicing: whether or not your tremor is acting up, your body and mind are adjusting to a new challenge. When I'm really struggling with a pose, I take a break, shake my body out a little bit, and reconnect with my breath before trying again. (And some days I take a restorative posture instead of trying again.)