No, according to the majority of experts, there's still no sound basis for claiming that the strains have different infectiousness and there's even less eviden

No, according to the majority of experts, there's still no sound basis for claiming that the strains have different infectiousness and there's even less evidence for different severity. The only thing known is that we can decode the genome across the world and that the virus, as it spreads, slowly gets some small changes which could be followed. There's no sign that anything people did (especially "lockdowns") up to now had any evolutionary effect on the virus. Coronaviruses mutate much slower than a lot of viruses. The majority of experts believe that what we observe (these still minimal changes) could be attributed to the "founder effect."