It depends on the person. In the "old days" the HRT regimen *was* generally only estrogen, but often prescribed in very high doses so that it could double as an anti-androgen. Estrogen does in fact suppress testosterone to some degree, but it varies in effectiveness by person - one woman I know is on very low dose E only (no spiro) and has a T level of 35, another is on a very high dose of E plus a super-high dose of spiro and still has T levels around 600.
(The woman who is on E-only also had a starting T level around 200, like you. But she reported that her "functionality" was impaired very early on - she's got fantastic results in terms of breast development, body fat redistribution, etc. but it stands to reason that if she's THAT responsive to estrogen, it'll also work on her downstairs the way higher doses do for others.)
So you can try, but there are no guarantees. Like anything in life, I guess.