The protection & restoration of our natural world is already unbearably dependent on voluntary work. Volunteers should be the special seasoning to the environmental work dish, not the staple ingredient.
To get the skills, focus, action needed we need more paid work, which won’t happen without funds

If we want to visit and enjoy our green and pleasant country without having to pay entry, then government budgets need to prioritise funding their green-ness and pleasant-ness.

There’s no other way they are going to get the money they need to maintain them, never mind repair and recover.