I've been using BoldBeast on a rooted Android phone for many years and that gave me the option after any call whether to save it or not. Having recordings has helped me recall all the finer details of calls whilst I've been mobile, and with retailers it has twice saved my bacon when I could prove the promises made verbally to me which did not materialise. I have no mercy with retailers as nearly all of them state they are recording my call, and they never acknowledge my immediate verbal response saying I'm doing the same my side (for quality and training purposes of course).
So recently I switched back to an iPhone (it's a long story) and did not want to jailbreak it as otherwise my banking app breaks. So the obvious choice without using an app, is a hardware device. After looking around, all roads seem to lead me to the PR200. It acts as a Bluetooth headset and does the recording on its own hardware which means firstly no jail breaking or rooting of the phone required, secondly no monthly subscriptions or additional costs, and thirdly it is iOS and Android compatible. Yes I could have bought a Dictaphone, but that is anyway cost, I must also carry it with me, and worse I must have all calls on speakerphone.
The PR200 is basically like a fat pen and the battery lasts 14 to 15 days. It has a switch for either off, auto record calls, or record a voice memo. It's good for 100's of hours but also easily plugs into any USB-A socket to charge as well as transfer the recordings. Good news is they also sorted out the date/timestamp for recordings.
On the downside it is not quite as clear as my phone's speaker and yes you do have to have it paired and carry it in a pocket with you. That said if you have a week-long meeting to record this does that job too with its 8GB storage and 576 hour recording time.