At the link below are my VSWR measurements (with and without an ATU) for my random long wire (RLW) configured as an ‘inverted L’ with 9:1 UnUn (used and measured at my previous QTH and at my current QTH but haven’t remeasured it).
The “9” side of the UnUn goes to the RLW and a short wire to a ‘dog lead’ screw-into-ground ground stake. A coax cable connects the “1” side to the rig.
A RLW has an ‘up and down’ VSWR pattern plotted against frequency so you will need an ATU.
I get good on-air results and one could easily use a RLW and UnUn when portable (although I usually take a tri-band EFHW when activating for convenience and quickness).
73 Andy