I've early 40s and been lifting heavy and eating in a surplus for a couple of months. Initially I lost an inch on my waist and gained cm's on my thighs and biceps. I fell off my tracking for a couple of weeks and it's crept up but that's ok as I'm doing another four weeks then going into a slight calorie deficit.
For me surplus looks like
30/40 (carbs)/30 macros tracked every day
c8% calorie surplus on my TDEE
3 heavy sessions of weights a week, plus 30 mins cardio
Average 10k steps a day
I also only eat unprocessed food pretty much, except a pea isolate drink. No added sugar, no refined carb, lots of greens, beans, lentils.
I don't know if you are like this but I find it VERY easy to go over on my fat intake so I have to watch this.
My deficit will probably be 50-100 calories under TDEE, but I would probably up the cardio sessions and steps a little too.
Workout wise I don't do abs really, only about 30 crunches a session, with no weights, as I am not looking to build muscle on my waist, but that's just me. Tbh the muscles get worked anyway through compound lifts, and my core is now strong AF.
Protein wise, typically I eat 40g oats for breakfast with a scoop of protein powder, 100g 0% greek yoghurt, almond milk, pumpkin seeds, blueberries, half a grated apple or carrot...
That's the first breakfast 🤣 then later I'll have a large egg, 50-100g 0% fat cottage cheese, drizzle of EVOO, with beans or seeded toast.
Snacks of apple and peanut butter, cottage cheese and pear. Lunches - home made bean soup, salad with a protein and carb, like quinoa and prawn, or black beans and tuna. Dinner the same. Lots of protein options...mackarel, seabass, cod, 5% beef mince, steak, salmon, pork, ham, chicken, turkey. Carb seems to be key - I'll gain less weight with beans and lentils, hence why I include those daily, I think they hang around for less time in the gut. I eat 200g of carb a day so defo don't fear carb. Especially not if you are lifting.
Bread wise I try to limit to a small slice as again most bread is pretty processed. I also eat tonnes of greens- if you start a meal with greens it lowers your blood sugar response (as does a spoon of white vinegar so I try to use that in dressings). I also do not snack at all in the evening after 8pm- the Zoe Nutrition podcasts found that was the worst for weight gain and actually eating often every 2-3 hours was not bad. I have tried intermittent fasting but it doesn't fit with my lifestyle as I get up about 5.30/6. Since I started weight training and macro tracking in May, my cholestrol has dropped 0.85.
So essentially I think it's small tweaks you are looking to make. Those biceps are popping!