Summary

Initially I was planning to print the holder by Username (https://www.thingiverse.com/thing:6304409), but it requires too much filament IMHO, so I've made my own version. I'm using the holder placed under my working desk, but guess it can be mounted vertically as well.

Print:
Printed in PETG. Elegoo Neptune 4 Pro has finished the job in 2h20m.

Mounting:
Screw one side with any 3mm screws, then slide a Mako in and cover it with the second side of print.

Print Settings

Printer Brand:

ELEGOO

                                            <p class="detail-setting printer"><strong>Printer: </strong>                     <div><p>ELEGOO NEPTUNE 4 Pro</p></div></p>                                                                                <p class="detail-setting rafts"><strong>Rafts: </strong>                     <div><p>Yes</p></div></p>                                                                                <p class="detail-setting supports"><strong>Supports: </strong>                     <div><p>No</p></div></p>                                                                                <p class="detail-setting resolution"><strong>Resolution: </strong>                     <div><p>0.24</p></div></p>                                                                                <p class="detail-setting infill"><strong>Infill: </strong>                     <div><p>15%</p></div></p>                                                    <strong>Filament:</strong> Syntech PETG

iFixit Mako Split Holder