Is it possible to forward a call from a messenger to a phone number?

Question

Messengers

Let's say: You're going abroad, but you want to call a LOT in your area. Skype, VoIP - this is understandable, but suddenly I thought. You leave at home an old or unnecessary android phone with your SIM card and a special application that receives calls that come from you over the Internet and redirects them to the telephone network to the desired number. I doubt very much that such an application exists, but you never know, can someone tell me something. There is no need to take the issue too seriously, you can just leave ideas.
And the following question, if anyone has experience in developing for android, is it difficult to bungle this on your own? I write in java & kotlin, but I don't have much experience with mobile.

Answer 1

Look at the following addresses:
www.raspberry-asterisk.org
https://ruvoip.net
Intelligibly, in Russian and English, all the possible functions of sip servers are outlined, and on what cheap hardware, if necessary, they can be run.
Well, or a multiphone, as they wrote earlier

Answer 2

For a megaphone - there is a ready-made one - eMotion (in the past, a multiphone) - calls, sms ( except for banking ones )
Most likely other operators are already ripening similar - competition with
p / s / he used both a multiphone and emotion - it’s quite normal
pps from the nuances to the present time: in fact, eMotion and multifon are the same, but ... if you get (or have long been received) a multifon account (it used to be for everyone, now only for corporations) - then outgoing calls will cost 1..1.5r , but if, being a physicist, activate eMotion, then everything will be exactly like in the tariff plan in the home region.