Hi, I start outdoor grows every year and can give you the following tips. First, make a transparent cover for your plants to prevent the rain from hitting them too hard.
Then, to combat aphids, ladybugs help as they eat the larvae and adult aphids. You can also make or buy a stinging nettle solution; this repels many insects and also serves as fertilizer.
You can also use companion plants like marigolds; they attract insects, and you can remove them when they're full of bugs.
For snails, you can use copper strips or beer traps; these attract the snails. After a few days, empty the traps and set up new ones.
Buy predatory mites against thrips and spider mites and hang the bags on the plants.
That covers the worst issues, and the rest can often be controlled by hand, like caterpillars, etc. But nature often takes care of these things itself. When there’s a balance, there’s no plague.
Hope that helps. Good luck!