Hello, I found some issues. But hey, only these!
I verified all airfields in Finland and read finnish AIP to found these.

THE LEVEL OF VFR FLIGHTS
4.5 VFR is fixed in FPL.
https://ais.fi/ais/vfr/gen_en/flight_plans.html#1003270

12.6 missing airfields, eg. EFMN, EFLL, EFLN, EFPA, EFVL, EFVP, EFVI
https://ais.fi/ais/vfr/aerodromes/aerodrome_toc.html

1.3 Missing FIR sectors, 1-7 FIR sectors
https://ais.fi/ais/vfr/gen_en/airspace_classification.html#1010287
and sector frequencies. See "TAMPERE RADAR" in
https://ais.fi/ais/vfr/gen_en/air_traffic_services.html#1003963

1.2.1 Missing Protection zones eg. around EFFO
https://ais.fi/ais/vfr/gen_en/airspace_classification.html#1003418

Closed RWs are missing like EFHJ, EFHI, EFJP, EFMP, EFVU
See link.
http://www.lentopaikat.net/english.shtml

Missing noise abatement area around Helsinki downtown. See VAC.
https://ais.fi/ais/eaip/aipcharts/efhf/EF_AD_2_EFHF_VAC.pdf
There are several abatement areas in Finland. Above is one example.

Missing two protection zones for industrial plants.
https://ais.fi/ais/eaip/pdf/enr/EF_ENR_5_3_EN.pdf

Nice to have feature
-Visualize upper air sounding balloons mentioned in the previous link. Would be nice if wind direction is used to shade probability of area where it might be.
- route warnings about bird migration. See.
https://ais.fi/ais/eaip/pdf/enr/EF_ENR_5_6_EN.pdf

Br.

The default option in SkyDemon is to generate VFR as opposed to a specific level in a flightplan. This option can be changed so a specific level is generated, at least it can in SkyDemon Plan, but usually people prefer to have the freedom to fly at any level.

Regarding the ACC frequencies, are these areas published within the AIP? We do include such things when they offer a Flight Information Service.

The ACC area coordinates, frequencies and call signas are published in AIP.
Here is a link to the AIP.