@Loquat ,
Suggestions for improving your chances
Assuming that you normally wish to have / leave Brave Browser > Shields: UP
Including the Global Shields Settings:

–
In a Brave Browser > New Window, go to: brave://settings/cookies
Disable: Clear cookies and site data when you close all windows
–
Next, go to: brave://settings/clearBrowserData
. . . and select the Clear browsing data > Basic tab.
Being as thorough as you believe necessary, select what you would clear and click on the Clear data
button. NOTE: the Clear cookies and other site data
selection (when Enabled) will sign you out of most websites.
–
Next, return to: brave://settings/clearBrowserData
For the Clear browsing data > On Exit tab:
Disable: Passwords and other sign-in data
Disable: Site and Shields Settings
Click on the Save
button.
–
In a Brave Browser > New Window, go to brave://settings/cookies
Scroll down that settings page, to Sites that can always use cookies
Click the Add button
Enter https://[*.]nimiq.com:443
as the site . . . but do not Enable
- Current Private session only
- Including third-party cookies on this site
Click the Add button
Repeat those steps for the following entries:
www.nimiq.com:443
–
Next, go to brave://settings/content/javascript
Scroll down that javascript settings page to Allowed to use javascript
Click the Add button
Enter https://[*.]nimiq.com:443
as the site . . . but do not Enable
- Current Private session only
Click the Add button
Repeat those steps for the following entries:
www.nimiq.com:443
–
In a Brave Browser > New Private Window, go to https://www.nimiq.com/
IF not already allowed in the site-specific Shields (Lion icon) panel, then Allow the source of blocked scripts: www.nimiq.com
- for example, click on the Allow
button:

–
If you observe the Brave Browser > Developer Tools > Network activity, you learn that somewhat-dynamic ordering of downloads from a website to Brave Browser, occurs. By “somewhat dynamic” I mean, that some items must download before other items.
If there is a glitch re the order of some downloads succeeding, then a state of security re the connection between the website and Brave Browser, may not yet occur . . . and thus, the padlock icon will not yet appear.
Instead, there is usually a circle with an orange/red field and an exclamation point within that, indicating that “this site is not secure”.
A reload of the web page, or closing the Brave Browser window, and using a Brave Browser > New Window -or- New Private Window - trying to connect to the URL address, again . . . may succeed.
Sometimes, determination is required, despite the frustration and delays. (I tend to be very determined, re this issue.)
Re your attempts to connect to https://www.nimiq.com/
, there is a a common www.nimiq.com
source for the many javascripts that are downloaded from the website to Brave Browser:
www.nimiq.com/js/custom.js
www.nimiq.com/_nuxt/app-69a546212f1f0fc673a3.js
www.nimiq.com/_nuxt/chunk-854c2f47a89c55a98d33.js
www.nimiq.com/_nuxt/chunk-4b48af934bc591b8d40e.js
www.nimiq.com/_nuxt/chunk-13de5600a85e0c89984a.js
www.nimiq.com/_nuxt/chunk-09059cdb492799802c2e.js
www.nimiq.com/_nuxt/chunk-b7e0b2cb6656caf55dd8.js
www.nimiq.com/_nuxt/chunk-a12523891f5b66f124b9.js
www.nimiq.com/_nuxt/chunk-af87d7cc6f9449913d70.js
www.nimiq.com/_nuxt/chunk-6dae216486a0ad16872b.js
www.nimiq.com/_nuxt/chunk-13ff09ccd96b9b2a9798.js
www.nimiq.com/_nuxt/chunk-c47133e7049065e07ab2.js
www.nimiq.com/_nuxt/chunk-02af646ef78519e3ef6b.js
www.nimiq.com/_nuxt/chunk-462929a9c0d97d935406.js
www.nimiq.com/_nuxt/chunk-fa6ca21ff413c68a172c.js
www.nimiq.com/_nuxt/chunk-df23452890580db0cda7.js
www.nimiq.com/_nuxt/static/prod/state.js
www.nimiq.com/_nuxt/static/prod/payload.js
www.nimiq.com/_nuxt/static/prod/manifest.js
www.nimiq.com/
A delay, or missing, download of a necessary javascript (or some other item that the website tried to send to Brave Browser), can result in a delay of, or halt, a successful appearance of the padlock icon.