Which Shooter Hero weapons are must-haves?

Hi everyone,

Long-time players which shooter hero weapons should I prioritize collecting and upgrading? I’m trying to decide between a broad strategy (upgrade a single versatile weapon) versus collecting many situational tools. Which weapons show the best long-term ROI for both solo and group play?

If you can name two weapons that performed well for you and why (damage profile, utility, or upgrade path), that would be super helpful for planning my upgrade path. Appreciate practical, experience-backed suggestions.

Thanks in advance.