Kids MTB gearing help

My 6y/o daughter has a Carrera Luna 20" and she's loving riding it.
Slight issue we're having at the moment is hills - she wants to do longer rides but after a while is struggling on the hills due to the slightly rubbish gearing on the bike.

Current gearing is 36t front and 7spd 13-28t on the back.

This set up give the following gear ratios:
High - 1:2.8
Low - 1:1.29

So on high when on hills she's still having to work quote hard.

Now my initial thinking is to just get a wider range rear cassette - these are available in either 12-32t, 14-34t and 11-34t.
This should help on the climbs as it brings thing closer to 1:1 at the low end (1:1.12 for 32t and 1:1.05 for 34t).

But I then got to thinking that I could improve things further by swapping the front ring. This would mean changing the crank - but I can get a 152mm Suntour with bolt on rings for £24 - and sticking a 32t single ring up front.

This would improve the climbing a bit more and would give a 1:0.9 ratio for a 34t cassette.

Question is, is it worth changing the front or should I just swap the cassette and see how she gets on?

The 'bike-tart' in me is thinking change the front a stick a purple chainring on for extra coolness and 'Dad points'.

So do I spend £12 on a cassette only or another £30 on new crank & ring?

Am I missing anything?