Why after so long of trying to get fit I have made literal zero progress...

>upper and lower 4 days a week program
Post program. Were you actually following it, including progression guidelines? How many calories a day is your maintenance, and how often did you overshoot? Do you actually have that info, or were you trying to eat "intuitively?"

Better yet, how long have you even been lifting?

> trying to maintain my weight

Greg Doucette got another one

Eat a moderate calorie surplus, then. You don't have to go the GOMAD route, you know. Especially not at 150.
Tell us your routine in full, as well as your method of progression. Current lifts would also help.

You have a lot of fat because you have no muscle because you don't eat so your muscles don't grow

Also do direct ab training

Upper Lower 4 day week a split
Body Workout #1
1. Bench Press: 3 sets x 5 reps
2. Pull-Up/Lat Pulldown: 3 sets x 5
3. Barbell curls 3 sets x 5
4. Dips 3 sets x 6–12 rep
Lower Body Workout #1
1. Squat: 3 sets x 5 reps
2. Leg press 3x12
3. Leg curls 3 sets x 6–12 reps
Upper Body Workout #2
1. Overhead Press: 3 sets x 5 reps
2. Pull-Up/Lat Pulldown: 4 sets x 6–12 reps
3. Close-Grip Bench Press/Dips: 3 sets x 6–12 reps
4. Dumbbell Row: 3 sets x 6–12 reps
5. Optional tricep exercise: 3 sets x 6–12 reps
6. Optional bicep exercise: 3 sets x 6–12 reps
Lower Body Workout #2
1. Deadlift: 3 sets x 5 reps
2. Front Squat: 5 sets x 5 reps
3. Optional additional leg exercise: 3 sets x 6–12 reps

Here
I’ve been pretty consistent since January. I’ve tried in the past but would usually give up after a few months but this time I feel I was doing a good job doing a routine

So you've been following a reasonable program for eight months, lost thirty pounds, and you're here asking if you need a personal trainer or gear? You need a reality check. You were a fat ass, now you're not, and that's more than most people manage to pull off in that length of time. Circle back to getting a trainer and gear once you've been consistent for two years and actually know what you're doing.

I lost that weight 2 years ago. Last years I was 140 but gain 10lbs then have been fluctuating between 150-155 lbs since

More or less this. Again OP, you don't have to pound back mcdoubles, but you do have to eat more otherwise muscles don't really have much leeway for growth.
And you've yet to share your progression scheme. Remember OP, as the body adapts to stress then stress needs to increase in order for it to develop more resilient stress adapations. You know, muscles.

Your sets are too easy and you're not eating enough.

3x5 on lat pulldowns?
3x5 on bench?

You need to up the ante, either add sets or reps or more weight on the bar. Nothing beats progressive overload and CALORIES:
The only way you're gonna grow as a natural.

Now don't go start eating 6000 calories of donuts or something dumb, all you need is to add 300 surplus calories.

Also forgot
> 3x5 barbell curls

No, no, no, the biceps need to be punished. I can guarantee you're undertraining your biceps.

3x5 is good for squats and deadlifts, but it's pretty shit for a lot of other exercises