They cannot legally force/mandate vaccinations, and they repeat that statement throughout the docs.
At most, they could insist that recovered people continue to get PCR tested: either you're negative and free to travel, or it will be a false positive, then you wait two (?) weeks and get a magical DHCP lease for 6-month "recovery certificate".
That would equate to a PCR-test industry tax on travel, which opens up several avenues for legal/policy challenge, e.g. test types, costs, subsidies, profit margins, supply chain ownership, benefits, numerical parameters, equipment calibration, performance (false positives/negatives).
Ludicrous rules don't punish people (who find workarounds), they decrease state power and credibility, reducing compliance with other, sensible, regulations. Sanity will eventually prevail, as long as citizens hold all policy proposals to high standards of transparency, reason and science.
Airplanes and hotels and tourist-destination cities want their customers back, and they will advocate on their behalf. The key is to avoid fights about specific interventions (like decade-old vaccines) and focus on laws (including liability) developed over centuries, and immune systems battle-tested even longer than laws.