If you want to keep the plastic style, go for a real handguard, the old school ones from brownells are a drop in IIRC:
https://www.brownells.co.uk/AR-15/M16/M4-SKINNY-STYLE-CARBINE-HANDGUARD-Skinny-M4-Carbine-Handguard-DOUBLE-STAR-Black-Polymer-Smooth-Drop-In-100004515
Same with stocks, go real spec. Though you may find a little wobble with certain styles, they won’t feel cheep or creaky.