Dropper post recommendations

Hey all,
I'm looking to get a dropper for my Merida ebig7. Mainly to get on and off easier. Amateur mtber so mot wanting to spend a lot. Based in NZ.
Post is 30.9 x 380.
Wondering what range in dimension post would be good and brand.
Currently looking at a Giant Contact Switch, TransX J22K4 and SDG Tellis.

https://www.pushbikes.co.nz/products/giant-contact-switch-dropper-post?variant=31390829215842

https://www.evocycles.co.nz/Product/274491/product?variation_id=317735&gad_source=1&gclid=EAIaIQobChMIreyzioLHiAMVo9EWBR2bSgIrEAQYAiABEgLuhfD_BwE&fbclid=IwY2xjawFqo-5leHRuA2FlbQIxMQABHTLTVecB87eM9fMVFDsMUGviOB0StdbxzBZMHuC1S5QcKd3sqI-Qnarcpw_aem_z3RSDFkv3GkbyvsxfM2rvA

Cheers