Are you setup in a closet or in a full room? I'd try to go with the smallest heater that you can possibly get away with, something that's well below the thermostat rating. It'll be better on your power bill for one thing, but it will also be a much smaller fire hazard and these things are already more hazardous than I'm really comfortable with. Ideally I think you would want a heating pad or the least/smallest heating device that you can get away with. Failing that I'd look at a smaller heater like the one in the tutorials (I think it's this one? https://www.amazon.com/gp/product/B074MXC3PN/ref=ppx_yo_dt_b_asin_title_o07_s01?ie=UTF8&psc=1)
This is a small electric heater. Some reviews mention using it in a car. Only 500W so might work with your inverter.
AmazonBasics 500-Watt Ceramic Small Space Personal Mini Heater - Blue https://www.amazon.com/dp/B074MXC3PN/ref=cm_sw_r_cp_api_fabt1_LUhVFb1BNMMTP
I had all the parts in my cart for a paint can heater at Home Depot... then realized it was going to cost me almost the same as an AmazonBasics space heater.
Put it all back and got the heater off Amazon, works well. I'm happy.
AmazonBasics 500-Watt Ceramic Small Space Personal Mini Heater - Blue https://www.amazon.ca/dp/B074MXC3PN/ref=cm_sw_r_cp_apa_i_dq7tDbJZ67YGM
I got this little guy. Just enough to take the chill off the corner of the cinderblock cave where my desk is, especially pointed at my feet, without being too obvious. https://www.amazon.com/AmazonBasics-500-Watt-Ceramic-Personal-Heater/dp/B074MXC3PN/ref=sr_1_4?dchild=1&keywords=space%2Bheater&qid=1606781996&refinements=p_89%3AAmazonBasics&rnid=2528832011&s=home-garden&sr=1-4&th=1
https://www.amazon.com/gp/product/B074MXC3PN
This is the one that I have. It's basically just a really small heater. You do have to plug it into an outlet. But, I find that it works really well. Just have to keep it very close, like, if I sit more than a foot away from it, I'm not going to feel it at all. But, if it's right next to me, it's actually very warm. You can put it on any surface you want to, it just needs to be really close to feel the warmth.
AmazonBasics 500-Watt Ceramic Small Space Personal Mini Heater - Blue https://www.amazon.com/dp/B074MXC3PN/ref=cm_sw_r_cp_apip_NvG5qKIfxHeVa
Inkbird ITC-308 Digital... https://www.amazon.com/dp/B01HXM5UAC?ref=ppx_pop_mob_ap_share
Probe comes with item #2, the temp regulator
20$
Not good enough for a living room. But, more than enough to keep a closet between 75 and 80:
https://www.amazon.com/gp/product/B074MXC3PN/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1
https://www.amazon.com/AmazonBasics-500-Watt-Ceramic-Personal-Heater/dp/B074MXC3PN/ref=pd_cart_vw_crc_2_9?_encoding=UTF8&pd_rd_i=B074MXC3PN&pd_rd_r=89f7c28b-0f73-49dd-91a8-5df1c6915ec3&pd_rd_w=rfjcc&pd_rd_wg=Y6XZL&pf_rd_p=087873c0-f5c2-4480-87ad-25ec8be526a6&pf_rd_r=ZRJE35N2CNMTJ0G2ZCMH&psc=1&refRID=ZRJE35N2CNMTJ0G2ZCMH and burlap may ward off frost for a month or so.
I use this for my 2x4x7 tent. It works great, I just set it on the ground outside the tent in front of the intake vent. AmazonBasics 500-Watt Ceramic... https://www.amazon.com/dp/B074MXC3PN?ref=ppx_pop_mob_ap_share