The Ohr HaChaim says that the Gadlus of Kalev, even more than Yehoshua, was that he had a big Yetzer Hara that he had to overcome. Kalev was Zoche to all kinds of Gevaldige Inyanim, like very long life, and so many Chashuva Doros (a dynasty), etc. The person with the big Yetzer Hara who works on himself is actually the luckiest. Many years later, Dovid needed a favor from Naval HaCarmeli, and Naval refused. He was a wicked person, and he was called a: כָלִבִּ י ש"א כה ג “Kalbi” i.e., a descendant of Kalev ben Yefuneh.
We can suggest that perhaps this is exactly Kalev's greatness; when we see how stingy and: צַ ַﬠ ן יִ רi.e., not Fargining and full of jealousy, and lack of Hakaras HaTov that Naval had, we see the potential evil of Kalev, since this is his descendant. Look how Kalev was full of Ayin Tova, saying טוֹבָה הָאָרֶ ץ מְ אֹד מְ אֹ דיד ז “The land is very, very good”, seeing only good in Eretz Yisroel and defending Moshe. He said that even if Moshe would give us ladders to go to the sky, we should listen to him.
And look how Naval talks and berates Dovidמִ י . רַ ﬠ וּבֲּבָדִ ים הַמִּ תְ פָּרְ צִים אִ ישׁ מִ פְּנֵי דָ וִד וּמִ י בֶן יִשָׁ י הַוֹיּם אֲדֹנָיו ש"א כה י Who is this Dovid? And who is this son of Yishai? Now-a-days there are so many servants who spite their master to his face (and for all I know, Dovid may be one of them). He is jealous of Dovid for being anointed Melech by Shmuel; he has no respect for anybody. He didn't acknowledge the favors that Dovid did for him, by protecting his flocks from lions and wolves.
The Gemara says about Yosef HaTzaddik that he was ready to sin with the wife of Potiphar. R' Elyashiv Zatzal brings down a Kashya in the name of the Mahralbach, We see how Chazal defend Tzadikim, like by Dovid they say ָלכּ הָאוֹמֵר דָ וִד חָטָא אֵינוֹ אֶלָא טﬠוֶֹהשבת נו א Dovid never did any sin whatsoever, and they deviate from the simple meaning of the Passuk that implies Dovid sinned. By Yosef the Passuk sounds like Yosef was a Tzaddik Gamur; why do Chazal go ahead and make him look like a potential: וֹףאֵ נ sinner, Chas V'shalom, who had to stop himself the last minute?
He answers that the truth is the opposite. If you are a born Tzaddik who refrains from sin, that's fine. But if you are a lustful potential sinner who stops himself, then you are much greater! This is so different than the way we think! So many of us suffer needlessly when we degrade ourselves, for so much Kin'ah, Ta'ava, Kavod, and Ka'as that's within us.
Don't look for Nisyonos! But if you already have, appreciate! And even if you fail often, this is the process, like it says: שֶׁ בַע יִוֹפּל צַדִּ יק וָקָ ם טז משלי כד A Tzaddik falls seven times, and gets up!
We are all human, and we all fall. The strong ones are those who aren't Nis'pael from their many sins, and even from super bad ones. He just keeps moving and trying. And in the end, he'll be Zoche to convert his sins into Mitzvos. (Chazal). And:ִ ים אֵין צַדִ יקִ ים גְמוּרִ ים יְכוֹלִין לַﬠֲמוֹדבְּ מָקוֹםשׁ ֶבּ ַﬠֲלֵי תְּוּשׁ בָה עוֹמְ דברכות לד ב Baalei Teshuva are even GREATER than pure Tzaddikim! Although in Ruchaniyus we try with the most Hishtadlus and loads of Tefila, yet we always exercise having Bitachon and more Bitachon, that someday I'll become the highest Madrega and the most purity.
Not being Mya'esh in Ruchaniyus is a very Chashuva Avoda, and you get plenty of Schar for it. And the Sefer HaMaspik L’ovdei Hashem says that the main Bitachon is in Ruchaniyus. There are many of us who spend a lifetime with their struggles and can get discouraged. Keep up the Bitachon without Yi'ush, your reward is priceless!