The material is interesting, there is no upsell, and you do get a fancy certificate by email.

@Bernard Reisz To clarify on your comment regarding rental property ownership and income not qualifying for a Solo 401k, is this the case even if you qualify for "material participation" in your properties?

Your mortgage payments may be fixed, but your taxes and utilities will increase, your maintenance material costs and labor rates for repairs have gone up, and your property is wearing out (appliances, flooring, water heaters, furnaces, roof, etc. all have a lifespan and will eventually need replaced). 

If you have given the contracdtor a deposit and that deposit has been used to purchase materials, & those materials are in your property I would;1.

I am no CPA (and you should consult with one) but how do you plan to meet the IRS material participation rule with a $400K W2 job. 

As an example, we were doing a charity project for a home owner that costs us $30 in materials but $210 in licensing and permits.

I did a simple Google search.Read this:What Is Material Participation?

As my avg rental period is <8 days, and I have <14 days personal use at the property and believe I can meet the material participation test, this should be a non-passive activity.Specific Questions on Material Participation:1) Do hours logged for material participation in 2022 include time prior to placing the property in service (i.e. first half of 2022)?

That is fine as a start, but only as a start.I emailed one of these companies to point out that none of their Youtube material cover the sale of our properties.

If you own the land outright, you can get a construction loan for labor and materials.