Im not sure if I understand you question exactly, but I have used both the tel:// and sms:// with no problems. The buttons work and highlight on hover as expected.
If you’d like to see what i mean, i’ve used both of the above buttons at https://affordablesydneyremovals.com.au
the SMS button near top of page and the TEL button near bottom of page when using a hand held (small screen) device. Is that whatyou need?