In principle YES, you can use it as storage for balcony power plants, but it is not weatherproof.
Are you looking for cables for the input (solar => Ecoflow) - for the output (Ecoflow => grid) there is not so much (safe! and smart) yet, as far as I know.

If you want to use it as a real storage tank, you can use the Ecoflow Powerstream. However, it is questionable whether this will ever pay off.
To charge the Ecoflow with the balcony solar you only need the XT60 to MC4 cable. Then you can connect solar panels to charge the Delta.
Please do not try to plug a 230v cable from the Delta into the socket to feed in power. This is life-threatening.