From this page of the Returnal guide, you will find out if you can carry more weapons during the game.
Playing the Returnal, you will find a lot of different weapons, but you will not be able to take all of them. During the exploration of the hostile planet Atropos, you will have to make many important decisions, and choosing he right weapons will be one of them.
Basic weapons sets
Selene may carry only one firearm and one blade. Every time you want to pick up another weapon (pistol, rifle, shotgun, etc.), the current one will be replaced.
Each time you find a new weapon, information about the weapon you are currently using (on the left) and the one you can pick up will be displayed on the screen. When comparing equipment, pay attention not only to bonus damage but also to the range, stability, and alt-fire.
Found or abandoned weapons remain where you leave them, and you can come back for them at any point of the Cycle.