Those are SRAMs. A 286 system wants DRAM, which is usually a lot cheaper.
https://www.geeksforgeeks.org/difference-between-sram-and-dr...
https://www.geeksforgeeks.org/difference-between-sram-and-dr...
Personally Im also a fan of keeping ram oldschool. I even reverse engineered a ram card for a 386 board just last week https://github.com/raszpl/386RC-16
(Re your 386 RAM board: Nice necroproject!)