For someone happy on MDI I can think of two things that ‘might’help that I know have worked for me or others.
Firstly splitting your langue to two doses can flatten out the spikes a little. I tried this last year and it helped me before I moved to a pump.
Secondly have you tried Levemir instead of Lantus? It’s got a different profile so may assist.
Obviously for both of these you’ll need discussions with your DSN and I hope you have a good one.
Fingers crossed you find a solution soon.