Perhaps you can try to place your LO's favourite toy at a distance to encourage crawling or place it at his/her chest level to encourage him/her to stand. If not, you may want to consider bringing your LO to the playground to build his/her muscle strength. Or have a play date session with other babies and that will also encourage him/her to crawl and stand.
Highly recommend solids! Purée food! Start with plain white porridge or sweet potato porridge first! Every baby different some fast some slow! My baby hates milk hahaha she loves solid!! She’s 9 months started solids from 6 months! She rather solids than my milk