On this picture on tyre threads, yes there is signs of 'cracks' specifically on the threads portion. None is found on sidewall.
These cracks on thread are normal and not affecting the structural integrity of tyres and hence it's safe for continuing use.
This sidewall has no cracks. Only severe and deep cracks at side wall that penetrates into the nylon fibre or fabric of tyres would have negative effects on structural integrity of tyres ....... which is NOT the case.

OP, don't be alarmed and kelam kabut my friend.

I'd used XM2 tyres upto 115,000 ish km over 6 plus years, no problem.

Yes, OEM says tyres are good upto 10 years. Pl search my previous upload on same here.

Edit:No safety issues here. Comfort, no comment as rubber compound are hardened in use.

No, I'd replaced them May last year with another batch of XM2 when the residual tread depth was about 2 mm vs the tyre manufacturers recommended 1.6 mm tread depth.

No uneven tread wear, despite inflating to 41 psi.

It's really value for money.