Nice to see that there is still someone here. Regarding your question, I only follow the classical Graeco-Roman cult. This means I ignore Mithras and identify Sol Invictus with Apollo. Anyway it is good to hear that there are still some old temples preserved in Dalmatia.
Vere dicis. Indeed the cult of Sol Invictus was extremely important for Roman history and religion and it shaped the Empire. But this is also a part of history that I do not particularly like, because Sol Invictus paved the way for Christ, whose worship kind of evolved out of Sol Invictus. If we look at the iconography the depiction of Sol Invictus and Christ (to some extent even Mithras) looked very similar, the rays of Sol became the halo of Christ. And behind both was the desire of a new savior who Rome was in need of at this time. For me personally it is a path I do not want to follow, so I stop at the Romanized Greek gods during the classical centuries.
On the other hand, if we come from a Christian environment, the concept of Sol Invictus might very well have a special appeal, since it is historically closer to us and probably appears a little bit more familiar.
There’s interesting video about Constantine Triumphal arch which had no Christian signs on it at all, but simply presentations of many Roman Gods. Some around 326 AD Constantine become Christian, while he made his arch next to Helios colossal monument just next to Colosseum.