I have one of these:
https://www.amazon.com/Maker-Hart-LOOP-MIXER-Portable/dp/B01M68UK38
May not be best sounding mixer but very convenient because it uses 3.5mm inputs and output.
How I do this is a combination of the maker hart loop mixer which gives me 3 outputs - headphones, rec, and master.
I run the rec out in to my tascam DR-5 recorder. https://smile.amazon.com/Maker-Hart-LOOP-MIXER-Portable/dp/B01M68UK38/ref=redir_mobile_desktop?ie=UTF8&aaxitk=9U3oRmMmqALRBQ1Ey9UK2g&hsa_cr_id=4836097260801&ref_=sbx_be_s_sparkle_mcd_asin_1
You could also use a cheaper mixer such as this and run it in to a handheld recorder. https://smile.amazon.com/ammoon-MX400-Ultra-compact-Channels-Adapter/dp/B01F6PTA04/ref=sr_1_8?crid=FJZR5CN50DF7&dchild=1&keywords=behringer+micromix+mx400&qid=1595796483&sprefix=behringer+micromix%2Caps%2C694&sr=8-8
I looked at this https://www.amazon.com/Maker-Hart-LOOP-MIXER-Portable/dp/B01M68UK38 It has pretty good reviews. I am currently using this https://www.amazon.com/Behringer-1202-BEHRINGER-XENYX/dp/B000J5Y282