It's not just about the number of drivers. Brexit cut us off from Europe's road hauliers.
Claiming that there is a shortage of HGV drivers across Europe, not just in Britain, makes a bit of a nonsense of their proposed temporary solution - trying to attract European drivers. Capped at 5k, it's hard to see that making much difference. They were made to feel unwelcome and unwanted in Britain, and now many have moved on. Why would they come back for some shaky temporary arrangement? That's before you consider why they might trust Johnson's crew not to renege at some point.
Perhaps large enough contracts might work, that will play well locally. It also fails to acknowledge that Britain was previously part of 'normal' HGV routes that cross the continent and back, until Brexit cut us off. These 'solutions' do nothing to restore these. The only long term answer is labour shortages in an ageing population is a more enlightened permanent policy.