Heart rate and weight loss question

I have a question about heart rate and figured this might be the place to ask.

Up until the last few years I've always had a fairly high resting heart rate (70+)
At one point in time I got it down to the high 50s but this was when I was cycling several hundred km a week.

Currently my resting heart rate is low 50s(52 - 54)
I first noticed it on my fitbit but not having much faith in that reading I used a garmin chest strap and got the same numbers.
Google tells me a heart rate under 60 bpm is considered bradycardia unless you are an endurance athlete.

I walk at a slow paced 5km a day, so pretty much in lazy bastard mode and have been for about 3 years now. 38 male so perhaps my metabolism is starting to slow a bit naturally.

There has also been a change to my weight loss, I'm about 4KG overweight and normally if I cut refined sugars the weight falls off me but not anymore.
I had my thyroid checked 6 months ago and that came back normal.

I hope this doesn't count as asking for medical advice but would a doctors visit be a good idea?

I'm just looking for feedback on if this sounds normal or not. Maybe just a natural change due to age?
Have others experienced this and is it just normal fluctuations based on age?