How much RAM to allocate in Minecraft?

I often play Minecraft with my friends on my Acer Aspire 5 laptop (Java Edition). I mostly had 30 fps, which is not much, but not that bad, because I only have a 60 hertz screen anyway. However, the game often dropped to 1 FPS for 15 seconds, which made it unplayable. (Yes, I use Optifine). Today I found out that you can allocate more GB of RAM to Minecraft (yes, I'm not very knowledgeable about computers). I have 8 GB of RAM and I would like to know how much GB to allocate.

So as far as I know half of it, I have 32 and then use 16 with you 4 then.

Ah okay, thank you, my friends, who are familiar with PCs, advised me that, but I just wanted to play it safe again.

I would also advise against using Optifine for more chunk distance.
That means reduce the display distance (not the field of view) and you immediately get more fps.

Instead of Optifine, you could also try out the Fabric Mod "Sodium" (https://www.curseforge.com/minecraft/mc-mods/sodium).

So far, the RAM has never really had an impact on the FPS for me