Honestly, might not be a popular opinion but I live in a big city and the amount of gardening-related local Facebook groups is insane. And since it's Facebook, it's all old people who have decades of experience with this shit. AND it's region specific so they are constantly throwing down relevant advice for the zone you live in. 10/10 it's literally the reason why I keep Facebook haha.

Try cherry and grape tomatoes. I've grown cherry tomatoes for the past two years along with starting grape tomatoes this year and I've had much more success with them than larger varieties. I think they tend to be more disease resistant, more vigorous, more productive, and fruit matures more quickly.

Also try growing them in bags or raised beds where it's kept away from the ground where pests can get at them easier. Another thing you can do is cover the soil around them with straw mulch in order to reduce soil splash onto the plant when it's being watered--this can transmit diseases to the plant. Pick off all the bottom half foot of leaves or so on the plant when it's big enough too to reduce soil splash hitting leaves.

Start them off inside, plant 3x as many as you want, choose the best and discard the rest when it comes to planting out.

Tomatoes grow well in containers or large pots, these can be moved to catch the sun or to avoid a storm and can also be moved away from some pests.

Cherry tomatoes grow well in hanging baskets...

You could look into: companion planting (some plants help or hinder others. Eg, basil and tomato are good friends); no-dig gardening (alongside having a good soil microbiome); green manure; sacrificial crops to lure pests away from your main crops; aspect and soil type.

Higher potassium and phosphates increase flower and fruit growth. Higher nitrogen increases leafy growth.

Don't grow the same type of plant in the same patch every year.

It's so hard to know any specific advice but I'd say when you're getting into gardening plant more than you need and try different things - ideally write on labels what you're doing with that one, like try some in bigger pots, different soil, more light or shade, different pruning styles or planting times. It's fun and a great way to get a feel for your plants, instead of thinking 'oh this plant is rubbish' try to come at it more like 'oh that's what happens to a tomato without enough light'

Also YouTube is full of great gardening videos, the lesson type ones get boring once you know what they're going to say but watching people show you their garden and talk you though everything and how it's been growing, what they've done too it and etc can be endlessly fascinating