going back chapters to get upgrades

[Tax evasion]

Hey,

So maybe a silly question, and a dumb one, but I'm quite curious.
I'm currently on my first playthrough, RH, on the TAIGA level, and trying to do the "Forest Child" achievement since I'm pretty much forced to stealth my way through.

I also noticed that I'm missing some good upgrades (extended filters, motion detector, etc.) because they were in areas I simply didn't check, because of low ammo mainly.

If I go back via the chapter selection, get the items, then load Taiga again (I'm at the beginning, so I can just start the chapter again, I barely got the night vision back), will I keep the items ? Or do I need to find them in the Taiga, just like I needed to find the night vision goggles again (because I lost my backpack at the bottom of the river) ?

Sorry if this question is quite confusing, I'm trying to make my life a tad easier, especially because I've heard you need to stack on filter for the DEAD CITY level.

[chakrapiercer]

If you reload an earlier chapter, you'll need to proceed from that, and do everything again, including what you already did in Taiga.

[Tax evasion]

Ah yikes, it's what I expected then.
Thank you !