You make some good points. Liens may not be the way to go. But I'm not convinced that a real UBI + universal healthcare funded by a wealth tax would be any less sustainable than the current situation.

Right now, those with too little to survive are often trapped in perpetual emergencies, at the mercy of economic predators, paternalistic government programs, and the incarceration industry. This segment of the population is growing, and the cost to taxpayers is high. From this post about it:

According to the National Alliance to End Homelessness, a person experiencing chronic homelessness costs the taxpayer an average of $35,000 a year (2016). In another study of 5,000 people experiencing Severe Mental Illness (SMI) and homelessness in New York City, the average annual cost of service use was calculated to be around $40,500 per person.

On housing alone, a major project in the Twin Cities provides tiny homes to the homeless at a cost of $45,000/person/year. Simply giving individuals a third of that amount would enable them to afford reasonable rent amounts.