So, the idea is a faster mining (1.5x faster) tougher (extra midslot) version of the Venture with the ability to field combat and mining drones. That exists in similar forms already; the Prospect and the Endurance, destroyers…
If you feel like you are not helping in a mining fleet then you need to accept that doing the best you can at the skill level you have chosen is a good contribution (your FC will appreciate any contribution - if he doesn’t then he’s the Muppet here). Alternatively there are other fleet roles in a mining fleet that are useful: if you are in a rat heavy area then combat support is useful. A hauler, such as a Miasmos (T1 Gallente specialist ore hauler) is always handy - it keeps the mining Command Ship on station providing bursts to the fleet while you take ore to a station.
If you are after a faster miner in a fleet then look at something like a Coercer or another turret destroyer. It’s got a small hold (not an issue if you’re in a well supported fleet, stay near the command ship and just push the Ore to it). It can probably be fitted for more mining rate than a Venture (CPU will be the challenge, but you can rig and fit modules to compensate). I’d also have a look at a Dragoon - it’ll probably match your proposal for mining performance in a fleet (five drones and three turrets with more low-slots, space in the drone bay for salvage and combat drones).
Talk to your FC. If you are helping the mining operation in being more efficient then he should be including you in the payout - and it can be more fun than just “Kill that Rock!”.
The Alpha player always has the choice of going Omega for the cost of a coffee a week - and in that way they actually support the game rather than just milking it. And please, for the love of god, don’t think you can grind for enough PLEX to go Omega - that way lies disappointed, burnout and rabid insanity.
(OK, that’s a nice coffee not instant disappointment in a jar).