I am still taking Actemra for GCA and PMR, but I stopped prednisone in the middle of August after being at that level for 4 weeks. After I stopped I had a few weeks of prednisone withdrawal - fatigue, sleep problems, and feeling depressed or irritable. But it seems like I've gotten past that now. Hopefully you won't have those problems since you will have taken a lot less prednisone than me.

Not to be discouraging, but I don't know what percentage of people with PMR can stop prednisone in one year or less without taking a biologic drug. Here's what google AI says:

While some people with polymyalgia rheumatica (PMR) can stop prednisone after one year, it is not typical, and the majority will require treatment for a longer period. Studies show that only a small percentage of patients are able to discontinue the medication by the end of the first year.
Reasons most people cannot stop after one year
Disease course: PMR is generally a self-limiting disease, but its active phase can last between one and five years. Many patients need medication for at least 1 to 2 years, or sometimes longer.
Relapses: Relapses are common, especially when tapering the dose. Some research suggests that up to half of all PMR patients will experience a relapse. In some cases, relapses can occur more than a year after stopping the medication.
Tapering schedule: Healthcare providers guide patients to taper off prednisone slowly to prevent withdrawal symptoms and disease flares. A common tapering goal is to reduce the dose gradually over one to two years.
Concurrent conditions: PMR can be associated with other inflammatory conditions, such as giant cell arteritis (GCA), which often requires a longer, more aggressive course of treatment.
Predictors for longer therapy: A patient's initial prednisone dose may be a factor. A study published in The Rheumatologist found that a higher starting dose was associated with lower odds of successful discontinuation after one year.

"A doctor told me that our bodies make 5 mg. a day but when on prednisone, I believe it quits making prednisone at some point--and that is why we have to taper slowly."
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The above statement is somewhat correct. However, the naturally occurring hormone that our bodies produce is called cortisol. Explaining everything that cortisol does is complicated. The following link explains it better than I can.
https://my.clevelandclinic.org/health/articles/22187-cortisol
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Cortisol is a corticosteroid

Prednisone is another corticosteroid.

Our bodies don't produce Prednisone. It is a synthetic chemical that is very similar to the naturally occurring hormone called cortisol. Prednisone is a substitute corticosteroid prescribed by doctors to manage inflammation by mimicking cortisol's anti-inflammatory and immunosuppressive effects. Taking prednisone causes the body to decrease or stop producing its natural cortisol.

Prednisone mimics the effects of cortisol but, with prolonged use, it causes the adrenal glands to suppress or stop natural cortisol production. However, the body needs a certain level of corticosteroid activity, which is provided by either natural cortisol or the prednisone medication.

Cortisol is NOT instantly turned back on after we take Prednisone for a long time. That is why we taper off Prednisone slowly.
https://www.mayoclinic.org/diseases-conditions/inflammatory-bowel-disease/expert-answers/prednisone-withdrawal/faq-20057923
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The problem is ... at lower doses of Prednisone (approximately 5 mg or less), the symptoms of a low cortisol level are very similar to the symptoms of PMR. It is very hard to know if PMR is still active or the symptoms are the result of a low cortisol level.

It can be extremely difficult to distinguish between a polymyalgia rheumatica (PMR) flare and adrenal insufficiency (low cortisol) when on low-dose prednisone (5 mg or less). Both conditions share many overlapping symptoms, such as fatigue, muscle and joint pain, weakness, and loss of appetite.