The simple answer is that Stalker 2's inventory system won't let you drop any items that you'll need for the main storyline quests, it simply doesn't allow you to drop, sell or store them.
There are however other items that you might need or are optional and might be used - there's normally a clue in the items description. For these perhaps consider storing them in your "magic" Personal Stalker Stash, the yellow box found at the major locations.
Anything in this box is accessible from any other yellow box or foot-locker, just like the inventory box in the Resident Evil games, allowing you to store what you want to keep but don't need in your immediate inventory, and have reasonably quick access to it by traveling back to the nearest major POI.
S.T.A.L.K.E.R. 2: Heart of Chernobyl Statistics For Scalespeeder Gaming
Currently, Scalespeeder Gaming has 73,134 views for S.T.A.L.K.E.R. 2: Heart of Chernobyl across 49 videos. His channel published less than an hour of S.T.A.L.K.E.R. 2: Heart of Chernobyl content, less than 0.02% of the total video content that Scalespeeder Gaming has uploaded to YouTube.
14