Any proof of ties will be less than the pull to avoid death by Russian bombs. If any applicant says the truth today it will be Purpose of Travel is to avoid being killed. But, as always, IRCC doesn't make any sense, instead of opening a refugee stream for Ukrainians, it tells to apply as usual by TRV, work visa, spousal sponsorship, etc.
I would not worry about any return ticket at this point, airspace over Ukraine is closed and nobody in their right minds is going to cross the border back on foot, unless you're joining the Ukrainian resistance. Just provide the proof of funds to cover the proposed length of stay and invitation letter. All the other proof such as property, employment, you provide as well, but at this point its kind of a joke because Russian bombs are destroying everything indiscriminantly and nobody is going to work but stay in bomb shelters.