@tuxedotrainer you’re ftp is low. when you train, you’re KJ are a function of power output and duration, so you’re really not burning that many KJ when riding, even for a while. So keep that in mind. Also, despite the hype, you don’t need so much on the bike nutrition if you’re only training for an hour or 1.5. It’s a big deal for longer stuff, but no doubt hyped up for recreational exercise.
As far as eating, take in a lot more carbs and fats. For example, your lunch / dinner with 200g rice and a piece of chicken is like 200 calories worth of complex carbs (100g cooked rice is around 100cal) and something like 400-500cap total. That’s just not that much food/energy per meal. Same with the sandwich snacks. If you’re having proper whole grain bread (not the tiny slices) then they’re like 100cal each, so a sandwich is around 300-400 depending on what you put into it.
I’d suggest dropping the idea of these baby bird meals all the time. I know it’s a ‘nutrition’ thing that’s popular and has been in fitness communities for years now, but eating til you’re full is really what you ought to do. If you feel full after pecking at one of these currently, it’s prob just bc you’ve mentally come to associate that sized meal with satiety (you can change that). Also, even if you keep your meals similar in structure, add a lot of fat to it, which is calorie dense (high calories to low weight in grams).
Also, your big weight gain has nothing to do with starting TR, unless this obsessive eating schedule is something you picked up when you decided to start training with TR. 68kg at your height is stick man level, and 83kg with that kind of ftp and a weight change that quickly suggests you just packed a bunch of body fat onto your frame. You’re not overweight even at 83kg, so lax the structured eating, add fats to these meals to up the calories, and drop the frequency.
For myself, I have a 600cal breakfast, 800cal lunch, usually a 800cal pre/post workout second lunch, then 800-1200cal dinner plus occasionally another 600-800cal post dinner ‘snack’. So we are talking 3000-4000/day and an eat about the same stuff everyday with minor deviations. I burn I’d say on average 800-1000cal from training 1-1.5hrs. All foods are ‘whole’ foods, but each meal is packed w fats and complex carbs. I don’t eat any ‘junk food’ or otherwise ultra processed stuff besides maybe sausages. I also eat food with fat naturally, don’t add it. Like I won’t add butter or cooking oil to something. I’ll just eat the real full flavored thing (like not buy lean chicken breast w no fat then add cooking oil so it’s not gross lol or eat very lean ground beef and add butter and/or cheese so it actually tastes good - do you see the irony in this common practice 
).
For example, I just had 1cup oatmeal (300cal), 1 scoop peanut butter (180cal), a handful of peanuts for crunch (160cal), 1 banana (80cal), and a handful of choco chips (150cal). Try eating meals like that. Buy full fat whole milk, yogurt, eat chicken thighs (not lean breast), 80/20 beef, pork sausages, etc. I might have a higher than normal metabolism, but if you’ve lived your life until now as a 183cm 68kg guy, so do you (I’m about 183, 74kg).