The CGT position on UK property gains depends on many different factors, for example, the availability of principal private residence relief, the availability of the Annual Exempt Amount for CGT purposes or other income affecting the underlying rate of CGT payable.
With regards to CGT reporting, some transactions must be reported within 60 days of contract completion on a separate HMRC system to that of Self-Assessment. Penalties can apply for late filing of this 60 day CGT report.
The CGT position of the sale of non-UK property may depend on your residence and domicile position as well as the other country’s domestic tax treatment.

HMRC’s guidance on cryptoassets is contained in their “Cryptoassets” procedural manual which can be found here.
Investment returns from cryptoassets may be subject to income tax, capital gains tax or both depending on the nature of the investment - for example, staking, trading cryptoassets or mining.

In general, trading between fiat currencies for personal use (as opposed to being a “currency trader” as a self-employment) is outside the scope of CGT. HMRC do not regard cryptocurrencies as currencies for these purposes. As such, any trade from one cryptocurrency to another (e.g. BTC to ETH) would be regarded as a disposal for UK CGT purposes.