I agree with your concern in isolation, however, I see it as more of a spread or balance of your current Keepers which is the main issue.
Ridley currently occupy D2; Hopper at M5 plus SEVEN forwards (JZ & Sheezle counted for now). I suspect that you've been losing your H2H battle via your Def line as your Ridley has been up against a Dawson type and possibly your D3 (Michalanney) up against another Keeper.
First thing I would do is to use the recent DPP additions to rebalance your structure (by moving players around through their DPPs), then assess where you need to upgrade to best benefit your team. I'll get it to something like the below...
D: Daicos Ziebell* Sheezle* Ridley Michalanney McKenna | Cowan Constable*
M: Oliver Bont LDU Petracca Hopper Ashcroft Ginbey* Wilmot* | Baker Long* Chesser*
R: Darcy Marshall | Madden*
F: Dunkley* Taranto* Rozee* Gulden* JHF* Chandler | Ratugolea* JVR
It doesn't look too bad now with Ridley at D4, Hopper at M5 & JHF at F5.
Chandler, Baker & Long to Roberts & Williams leaves you with $534,500 (based off your proposed trade in post #234) for the upgrade. You can afford LLoyd but have to raise more $$$ (Ginbey over a Baker/Long) to get to Sinclair. As for a forward, you can afford anyone except for Cameron and Moore.
Let's say you use Ginbey in lieu of Long in the above, this will increase your bank to $588,000 for that upgrade which opens up some MID options for you (not the Neale/Laird which you desire): Serong, Cripps, Parish, JKelly, Macrae
Anyways, I feel that your team is not as dire as first thought. Yes, you're missing a couple of blue chip premiums right now, however, the overall balance (after restructuring) is okay PLUS you have a good core group of cash cows to allow you to gradually chip away at improving your team and overall scoring potential.