Will doubling the price & damage of grenades make them balanced compared to other weapons?

Context: I’m running a group through the Dead Suns adventure path. This is the first time any of us have used Starfinder. One of the party members is an ysoki envoy who would like to focus on grenades for damage (inspired by this question). It’s a party of 6, so I routinely give bonuses to named/solo foes and increase the number of mooks in encounters.

The group has reached level 5, and we’ve noticed that grenades just don’t do a whole lot, though. Our solarian routinely wallops enemies for 30+ damage per round, and can Supernova for 6d6 damage. Meanwhile the envoy is chucking around looted Mk1 grenades that do 1d6 or 1d8 damage or purchased Mk2 grenades that do 1d12 or 2d6 damage. In a recent fight, their enemy was able to make effective use of grenades only because 5 mooks threw grenades at the same time (and even then most of the party members struck took about 15 damage, since the saves were easy).

Proposal: I’m thinking about adding an “Elite” version of all damage-dealing grenades that costs twice as much and deals twice as much damage. As an example, the Mk1 Shock Grenade is a level 1 item costing 130 credits that deals 1d8 damage; the Elite Mk1 Shock Grenade would also be a level 1 item but would cost 260 credits and deal 2d8 damage. Foes important enough to have a name who carry grenades would carry the elite versions, while faceless mooks would use the normal versions.

Looking at later levels, an Elite Mk5 Frag Grenade would be a level 14 item costing 37.5k credits and dealing 20d6 damage. That sounds like a lot of damage, but almost any character could spend 72.3k credits and proficiently wield an Advanced Seeker Rifle, a level 14 longarm that deals 6d8 damage per shot. It seems like elite grenades would be highly effective from an action economy perspective, but too expensive to be used casually (which is how grenades probably should work, really).

Is this a viable change or am I overlooking anything?